Improvement in stair-builders  rules



s. 1. ROBINSON.

j Stair-Builders Rule. N0. IW0g4'7. l Patented March 2,1875.

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ATTURNEYS.

THE GRAPHIC C0.PH0T0A-LITH.39&4I PARK PLAGEJLYA JNrrnn STATES FFIC.

ATENT IMPROVEMENT IN STAIRBUILDERS RULES.

Specification forming part of Letters Patent No. 160,47 l, dated March2, 1875 application led December To all whom it may concern:

Be it known that I, JOHN J. ROBINSON, of Orange Court-House, in thecounty of Orange and State of Virginia, have invented a newr andImproved Stair-Builders Rule; and I do hereby declare that the followingis a full, clear, and exact description of the same, reference being hadto the accompanying drawing, forming a part of this specification, inwhich- Figure 1 is a vertical elevation of the rule presenting its edge,and showing two sides Ot' the same. Fig. 2 shows the application of therule to stair-building.

The Object of my invention is to provide a rule for stair-building; andit consists in the peculiar construction of a device, by the use ofwhich I am enabled rapidly and accurately to construct and tit thebalusters to the handrails uniformly, and in proper position.

In the drawing', A represents a square rule having' at the middle thelongitudinal spirit level B, and at one end the transverse spirit. levelO. D is a slot upon one of the adjacent sides, which is preferably linedwith metal to prevent wear, and which extends the greater portion ofthelength of the rule. In said slot moves the binding-screw E, which isattached to a graduated extension-rule, F, which slides inside rule A,and is provided upon its end with a prickingpoint. G is a second slot onthe same side of the rule, in which slides a second binding-screw, H,which is in a like manner attached to an incased adjustable base-stud,I, that moves in rule A, as does the extension-rule, and is similarlyprovided with a pricking-point.

In the operation of stair-building the useful application of theabove-described rule is as follows: The chief object of its constructionis to secure the length of the baluster from the step to the hand-railin a perpendicular line, and to accomplish this the prick of the stud isallowed to project a short distance from the bottom of the rule A, inwhich position it is held rigidly by the thumb-screw H. The ruleA isthen placed upon the stair-step, with the prick upon the spot where thebaluster is to go, and the exact perpendicular position of the said ruleis observed by means of the spirit-level C. As soon as this is securedthe extension-rule F is elevated by means of the binding-screw E untilthe prick strikes the hand-rail, marking the place to be bored for thebaluster. The bindingscrew is then tightened, the stud loosened, and therule withdrawn.

By means of the above-described method the position of the socket in thehand-rail is determined, and also the length of the baluster fromshoulder tO shoulder.

The instrument may be used also for other purposes, as leveling andplumbing, Sto., the spirit-level B adapting the same to ordinaryleveling purposes, and the spirit-level O to plumbing'.

Having thus described my I claim as new is- The improved stair-buildersrule consisting of the case A, spirit-levels B and O, extensionrule F.and adjustable stud I, provided with a prick, all combined and arrangedsubstantially as shown and described.

JOHN JONES ROBINSON.

invention, what Witnesses A. THOMSON, RICHARD CHAPMAN.

